Refrigeration



G. 'GRoss REFRIGERATION Filed Nov. 25, 1938 2 Sheets-Shet 1 ll llllllllllllllllllllllll INVENTOR A lfz "ed 6. Gross ATTORN EY Nov. 11, 1941. A. G. GROSS REFRIGERATION Filed Nov. 25, 1938 2 Sheets-Sheet 2 lI/III/I/III/l/l/IA VIII/l/l/A 71/ Ill/ll I I ii H III/III III/III! //I//////////, 'II/ Ill INVENTOR Alfred 6'. Gross ATTORNEY Patented Nov. 11, 1941 REFRIGERATION Alfred G. Gross, Chicago, 111., assignor to The Hoover Company, North Canton, Ohio, a corporation of Ohio Application November 25, 1938, Serial No. 242,224

14 Claims.

This invention relates to the art of refrigeration and more particularly to a novel evaporator construction and control therefor particularly designed for use in absorption refrigerating systems.

It is a principal object of the present invention to provide a refrigerating system including an evaporator provided with a plurality of individual ice-freezing sections and a low temperature fast-freezing section which is so constructed and arranged that the production of refrigeration in the ice-freezing sections, the supply of liquid refrigerant thereto and the flow of inert gas therethrough are controlled entirely by mechanisms arranged and sealed within the system and in which the supply of liquid refrigerant to the individual ice-freezing evaporator sections is proportioned by means of a pumping mechanism which is also utilized to elevate liquid refrigerant to the elevation of the evaporator from the bottom of thecondenser.

It is a further object of the invention to provide an absorption refrigerating system of the type above referred to in which measured quantities of refrigerant liquid are supplied to various portions of the refrigerator circuit by means of a twin gas lift pump mechanism acting in conjunction with a control mechanism sealed within the system.

Other objects and advantages of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawings, in which:

Figure 1' is a diagrammatic representation of an absorption refrigerating system embodying my invention in which the evaporator is shown on an enlarged scale and in perspective.

Figure 2 is a sectional elevational view of a control mechanism and certain portions of the evaporator.

I Figure 3 is a broken partial sectional side elevational view of the evaporator and the associated control mechanism.

Figure-4 is a partial sectional view 'on an enlarged scale of a portion of the control mechanism.

Figure 5 is a partial sectional view on an'enlarged scale of another portion of the control mechanism.

Referring now to the drawings in detail and first to Figure 1 thereof, there is disclosed an absorption refrigerating system comprising a boiler. B, an analyzer D, an air-cooled rectifier 'R, a tubular air-cooled condenser C, an inclined tubular air-cooled absorber A, a gas heat exchanger G, an evaporator E, a liquid heat exchanger L, and a circulating fan F which is driven by an electrical motor M. The above described elements are suitably connected by various conduits to form a plurality of gas and liquid circuits constituting a complete refrigerating system.

The above described refrigerating system will be charged with a suitable refrigerant, such as ammonia, a suitable absorbent, such as water, and a suitable inert pressure equalizing medium, preferably a dense gas, like nitrogen.

The boiler B may be heated in any suitable manner, as by a gas burner or an electrical cartridge heater. Any preferred control mechanism may be provided for simultaneously controlling the energization of the motor M and the heater for the boiler B in response to variations in temperature of the space to be refrigerated. A preferred control mechanism is disclosed and claimed in the co-pending application of Curtis C. Coons, Serial No. 148,424, filed June 16. 1937, now Patent No. 2,228,343, issued January 14, 1941.

The application of heat to the boiler B generates refrigerant vapor from the strong solution therein contained. The vapor so generated passes upwardly through the analyzer D in counterflow relationship to strong solution flowing downwardly therethrough from which further refrigerant vapor is generated by the heat of condensation of absorption solution vapor liberated in the boiler. The refrigerant vapor is conveyed from the analyzer to the upper portion of the condenser C by means of a conduit I I which includes the rectifier R. I

The weak solution formed in the boiler by the generation of refrigerant vapor is conveyed therefrom to the upper portion of the absorber A through the conduit I2, the inner path of the liquid heat exchanger, and a conduit I 3. It is apparent that the upper portion of the absorber is at an elevation appreciably above the liquid level normally maintained in the boiler-analyzer system; wherefore some means must be provided to elevate the absorption solution thereinto. For this purpose a small bleed conduit 18 is connected between the discharge conduit 11 of the circulating fan F and the conduit I3 below the liquid level therein whereby the absorption solution is elevated into the absorber by gas lift action.

The Weak solution flows 'downwardlythrough the absorber in counterflow relationship to a pressure equalizing medium refrigerant vapor mixture flowing upwardly therethrough. The refrigerant vapor content of the mixture is absorbed by the solution and the heat of absorption is rejected to the air flowing over the outer surface of the absorber conduit and the air-cooling fins mounted thereon. The strong solution formed in the absorber flows to the bottom portion thereof through which it is drained through the conduit 18, the outer path of the liquid heat exchanger L, and the conduit 19 into the upper portion of the analyzer D.

nulating fan 2 aaeaese struction and operation of the evaporator will be described in detail hereinafter. For the present it is sufiicient to state that the inert gas flows therethrough in contact with liquid refrigerant which evaporates to produce refrigeration and the resulting rich gas is conveyed from the evaporator through the conduit into the outer path of the gas heat exchanger G. The rich gas is conveyed from the outer path of the gas heat exchanger G to-the bottom portion of the absorber A by a conduit 26. The rich gas then flows upwardly through the absorber A counter to downwardlyflowing absorption solution in the manner described heretofore.

The evaporator E comprises a control chamber 38 which is provided with U-shaped inclined icefreezing coils projecting forwardly thereof which are designated as 3| and 32 on the left and right hand sides thereof respectively, as viewed in Figure 1. The evaporator alsoincludes' a horizontally positioned fast-freezing coil 33 which underlies the above mentioned coils 3| and 32 and communicates at one end with the bottom portion of'the control chamber and at its other end with the inert gas discharge conduit 25.

The control chamber 30 is divided interiorly thereof by suitablepanels into a pair of refrigerant storage chambers and 36 in the top portion thereof, an intermediate control and inert gas supply chamber 31 and a bottom inert gas discharge chamber 38. The upper legs of the conduits 3| and 32 communicate with the cham- 32 communicate with the chamber 38. The inert The liquid refrigerant storage chambers 35 and 36 are provided with overflow and level limiting conduits 53 and 54, respectively, which join the bight portion of the twin gas lift pump.

' The control chamber 36 is provided interiorly thereof with a venting duct 55 which is in com munication with the upper portion of the chambers 35 and 36 by means of small transverse conduits 56 and 51, respectively. The ventingduct 55 is connected to the principal vent conduit 42 whereby to remove the pumping gas from the upper portions of the chambers 35 and 36.

/The bottom portions of the liquid refrigerant supply chambers 35 and 36 communicate respectively with a pair of plug valves 60 and 6|. The valves 68 and 6| are 'each provided with actuating stems 62 which are surrounded by compression springs 63 connected to urge the valves to open position." -The valves are arranged within the control chamber 31 with the actuating stems 62 facing each other and spaced a slight distance apart.

The valve 68 is provided with a discharge conduit 65 which opens into an opening forming a continuation .of the evaporator conduit 32 in a boss 66 formed on the inner wall of the compartment 3!). The discharge conduit 61 of the valve 6| is arranged in a similar manner andwill not be described in detail.

Each boss 66 is provided with a bearing surface 68 surrounding the end portion of the opening communicating with its associated evaporator conduit which is adapted to receive an actuating link 69 which is also provided with an opening gas supply conduit'23 communicates with the nert gas inlet and control chamber 31.

The refrigerant vapor supplied to the condenser C is liquified therein by the cooling air flowing over the outerwalls of the fins thereon and is discharged from the bottom thereof into a conduit 48. The bottom portion of the condenser is vented to the rich gas side of the heat exchanger G by means of a conduit 4| which joins a principal vent conduit 42. An overflow conduit 43 is connected between the rich solution return line 9 and the top part of the bottom conduit of the condenser C.

' The liquid refrigerant condenser discharge conduit 40 extends downwardly slightly below the bottom portion of the condenser C and communicates with the bight portion 45 of a U-shaped twin gas lift pump having elevating conduits 46 and 41 extending upwardly on the left and right hand end of the bight conduit 45, as viewed in Figure 1. The vertical elevating conduits 46 and 41 pass through the rear wall of the control chamber 38 and discharge into the chambers 36 supplied to the bight'portion of the conduit 50 by means'of a small bleed conduit 5|- which is connected to the discharge conduit |1 of the circorresponding with the opening in the boss 66. The actuating link 69 is maintained in position by an overlying retaining plate 10 which is secured to the boss 66 and is also provided with a central opening. 'The boss 66 is provided with an inwardly projecting flange 1| to retain the link 69 in place. The flange 1| is provided with a broken away portion at its bottom to receive the projecting arm portion of the actuating link i passageway in the boss 66 receives a spiral bimetallic thermostat 13 which is attachedat 12 to. the actuating link 69. It will be'understood that the conduit 3| is provided wi h a similar thermostat which is also attached to an associated actuating link 69.

The free end portions of the links 69 are pro vided with pins 15 which are received in elongated slots 16 in the end portions of links 11 which are pivotally connected to a rocker link 18 in the center of the control chamber 31. The

free end of the rocker'link 18 is connected by means of a tension spring 19 to a gas and liquid flow control element 80. The element 8 8 is pivoted at 8| in the central portion of the chamber 31 and is provided with angulaily related arms 82 and 83 which are designed to cooperate respectively with' the gas inlet open ng to the ice-freezing evaporator conduit 3| and 32. The

arms 82 and 83 are angularly related in such fashion that only one of the conduits 3| and 32 may have its communication with the chamber 31 interrupted at any one time. The central portion of the element '88 is provided with an upstanding ear 84 to which the spring 19 is connected. The ear 84 is provided on opposite sides thereof with small pressure plates 85 and 86 which are designed to cooperate with the actuating stems 62 of the plug valves 60 and 6|, re-

spectively.

The arrangement is such that whenever one of the arms 82 or 83 is swung upwardly into the position indicated in Figure 4 to establish communication between its associated evaporator conduit and the interior of the chamber 31, the element 84 will move to position to permit the valve element associated with the opened evaporator conduit to move to open position and to close the opposite plug valve element.

As is illustrated, the evaporator conduit element 33 communicates with a downwardly extending corner of the chamber 30 into which the lower end of the ice-freezing evaporator conduits 3| and 32 open. The evaporator conduit 33 lies in the top portion of an insulated fastfreezing chamber 89 and is separated from the storage space of the chamber 89 by a plate 90.

The ice-freezing evaporator conduits 3| and 32 are each provided with a plurality of spaced inclined freezing plates 9| which are adapted to receive the inclined bottom portion of a water tank 93. The tank 93 also rests on the insulated top portion of the insulated chamber 89 and abuts the front face of the control compartment 30 at its rear end.

It will be understood that the present apparatus will be installed in a suitable cabinet construction. Preferably the absorber, boiler and analyzer will be suitably distributed in a mechanism compartment which is positioned beneath the cabinet storage compartment and the condenser and associated conduits will be positioned in a vertically extending rear cooling air flue.

The evaporator will extend forwardly in the top central portion of the storage cabinet with the control box 30 either lying substantially flush with the rear wall of the cabinet or embedded in the insulated window in the rear wall of the cabinet which provides for insertion of the evaporator structure thereinto. If desired, the front wall of the control box 30 may be positioned flush with the front wall of the cabinet window insert whereby the box 30 occupies no space within the storage compartment of the refrigerator,

The operation of the invention is as follows: Assuming that the apparatus has not been operated and that the refrigerator cabinet is warm, both thermostats 13 will be turned to a position tending to move the control mechanism in position to supply inert gas and liquid refrigerant to its associated evaporator. Under these conditions the over-center mechanism, because of the slight bias of the snap-acting spring 19, will have actuated the element 80 to one side or the other of its two possible positions. that the element 80 is in the position illustrated in the drawing, liquid refrigerant discharging from the condenser to the conduit 40 will be divided into two streams by the twin lift pumping mechanism and will be discharged in two streams into the refrigerant chambers 35 and 36. The refrigerant discharged into the chamber 36 will simply collect therein until it has reached the level of the overflow drain 54, but the liquid discharged into the chamber 35 will flow its associated plug valve 60 and conduit 65 into the ice-freezing evaporator element 32.

The liquid refrigerant will flow through the ice-freezing evaporator element 32 either by gravity or under the impetus of the inert gas stream flowing therethrough as may be desired. If gravity circulation is desired, the various evaporator conduits will be sloped slightly in an through.

Assuming appropriate direction to provide this form of liquid refrigerant flow. If positive circulation of the liquid refrigerant through the evaporator conduit is desired, a 'relatively small conduit will be utilized in order that the inert gas may flow therethrough at a velocity sufliciently high to drag or sweep the liquid refrigerant in a stream along through the evaporator conduit. The manner in which this form of propulsion may be achieved is disclosed and claimed in the co-pending application of Curtis C. Coons and William H. Kitto, Serial No. 386,395, filed April 2nd, 1941.

The liquid refrigerant and inert gas flow through the conduit 32 and the liquid evaporates to produce refrigeration therein. The refrigeration so produced eventually produces ice blocks on those portions of the inner wall of the tank 93 which are in direct thermal contact with the freezing plates 9| carried by the evaporator conduit 32. Any liquid refrigerant not evaporated in the evaporator conduit 32 is discharged into the inert gas chamber 38 along with the inert gas and is drained therethrough into the inlet conduit of the evaporator 33 through which it flows either by gravity or under the propulsion of the inert gas stream as before. This remaining liquid refrigerant evaporates in the conduit 33 to refrigerate the heavily insulated chamber This operation continues unabated until such time as ice blocks of a predetermined size shall have been formed in the water tank 93 whereupon the thermostat 13 associated with the icefreezing conduit 32 will actuate the link 69 in a counterclockwise direction, as viewed in Figure 4, which will permit the thermostat 13 associated with the inoperative evaporator conduit 3| to actuate its associated plate 69 in a counterclockwise direction, as viewed in Figure 2, which will thereby shift the linkage I1, 18 and will rock the plate in a clockwise direction about its pivot 8| whereby the arm 83 will discontinue the flow of inert gas through the conduit 32, the arm 82 will move away from the opening permitting inert gas to flow through the conduit 3|, the valve 6| will move to open position .under the'bias of spring 63 and the pressure plate 85 will abut the stem 62' of the valve 60 and move the same to closed position.

Continued operation of the apparatus now causes a'continual discharge of liquid refrigerant into the chambers 35 and 36. The liquid discharged into the chamber 35 merely collects therein whereas the liquid discharged into the chamber 36, as well as the liquid previously stored therein, flows through the valve GI and conduit 61 into the evaporator conduit 3| to produce refrigeration in the manner heretofore described in connection with the evaporator 32. When ice blocks of a predetermined size have now been formed in those portions of the water tank in heat transfer relationship with the evaporator conduit 3|, the associated thermostat 13 will move the associated arm 69 in a clockwise direction, as viewed in Figure 2, which will permit the thermostat l3 and arm 69 associated with the conduit 32 to return the control mechanism to the position illustrated in Figures 2 and 4 which will again cause production of refrigeration in the ice-freezing evaporator conduit 32.

It will be appreciated from the above that the initial cycle of the apparatus is apt to be relatively prolonged because of the fact that there was no original supply of liquid refrigerant in the storage chamber 35. However, once the ap paratus has gone through one complete cycle of operation, one or the other of the storage chambers will always be charged with liquid refrigerant when the apparatus is energized by the control mechanism which is responsive to boxtemperature refrigerating demand.

Due to the fact that only half of liquid refrigerant supplied by the condenser at any one time is discharged directly into an operative evaporator section, approximately half'the total refrigerating effect required in any one operative cycle for either of the ice-freezing evaporators is supplied by liquid refrigerant stored in its associated liquid storage chamber during the inoperative cycle thereof. The valves 60 and BI and their connecting conduits are so proportioned as to permit liquid to flow from the chambers 35 and 36 at the proper rates.

The storage compartment is refrigerated by air circulation over the wall 01 the water tank '93 which are made extensive for this purpose.

- Due to the fact that the walls of this tank are not at a very low temperature the relative humidity within the storage compartment will be maintained at a relatively high value whereby to prevent undue drying of foodstuffs. The extensive area of the water tank provides efiicient storage compartment cooling at the relative high temperature thereof.

Though the twin gas lift pump which supplies refrigerant to the evaporator has been illustrated as being substantially coextensive in height with the control chamber 30, itis by no means necessary to limit the height of the gas the construction or operation of the evaporator and the rest of the system.

The fast-freezing evaporator receives only refrigerant which has not been evaporated in the ice-freezing evaporator sections; however, this does not impose a detriment on the fast-freezing evaporator for the reason that the same operates within an insulated compartment and is not normally called upon to carry heavy refrigerating loads, though it is capable of carrying such loads should occasion arise.

The present invention provides an absorption refrigerating system which is constructed and arranged in such fashion that the liquid refrigerant discharged by the condenser is simultaneously elevated to a desired height and divided into two equal streams which discharge into a control chamber for ultimate utilization in separate evaporator sections. Additionally, the various evaporator sections are controlled properly in accordance with demands for refrigeration by mechanisms sealed entirely within the refrigerating system and which are simple and positive in operation.

The small twin gas lift pump provides a very efficient and reliable mechanism whereby the stream of liquid refrigerant discharged from the condenser may not only be equally divided but may also be elevated to the height of the evaporator. 1

By the arrangement herein disclosed the inert gas flow and the liquid refrigerant flow are simultaneously controlled or limited to selected paths within the evaporator by a single simple mechanism under the control of a pair of simple thermostatic elements.

Though the apparatus has been disclosed herein in considerable detail, it is not limited to the actual construction shown and various changes may be made in the arrangement, construction and proportion of parts without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. Refrigerating apparatus comprising a plurality of evaporators, liquid refrigerant supply means, means for simultaneously elevating liquid refrigerant from said supply means to said evaporators in the form of a plurality of individual bodies, means for circulating a pressure equalizing medium through said evaporators, and

thermostatic control means for directing a selected one of said bodies of refrigerant into a selected one of said evaporators.

2. Refrigerating apparatus comprising a plurality of evaporators, liquid refrigerant supply means. means for simultaneously elevating liquid refrigerant from said supply means to the level of said evaporators in the form of a pluralty of individual bodies, and thermostatic control means for directing a selected one of said bodies of refrigerant into a selected one of said evaporators.

, of said evaporators in the form of a plurality of ind vidual bodies, means for circulating a pressure equalizing medium through said evaporators, and thermostatic control means for directing a selected one of said bodies of refrigerant into a selected one of said evaporators, said elevating means discharging into a plurality of storage chambers each of which is connected with one of said evaporator sections. and is under the control of said thermostatic control means.

4. Refrigerating apparatus comprising a plural ty of evaporators, liquid refrigerant supply means. a twin gas lift pump connected to elevate and divide liquid refrigerant from said supply means, and means for intermittently supplying the dscharge of a selected one of said pumps into a selected one of said evaporators.

5. Refrigerating apparatus comprising a plurality of evaporators, liquid refrigerant supply means, a twin gas lift pump connected to elevate "and divide liquid refrigerant from said supply means, means for directing the discharge of a.

selected one of said pumps into a selected one of said evaporators, said last mentioned means comprising storage chambers into which said pumps discharge, and means for controlling the of sad evaporators, said last mentioned means com risng storage chambers into which said pumps d'scharge, means for controlling the discharge of said storage chambers, and overflow means connected to the inlet of said gas lift pump for limiting the liquid level within said storage chambers.

7. Absorption refrigerating apparatus comprising a solution circuit including a boiler and an absorber, a pressure equalizing medium circuit including an evaporator and said absorber, power driven means for circulating a pressure equalizing medium through said pressure equalizing medium circuit, means for liquefying refrigerant vapor generated in said boiler, said evaporator comprising a plurality of individual sections, a storage chamber connected to each of said sections, a twin gas lift pump connected to receive liquid refrigerant from said liquefying means and to discharge separate and equal streams thereof into each of said storage chambers, means for directing a portion of said pressure equalizing medium into said twin gas lift pump to operate the same, and thermostatic -an absorber, a pressure equalizing medium circuit including an evaporator and said absorber, power driven means for circulating a pressure equalizing medium through said pressure equalizing medium circuit, means for liquefying re- .frigerant vapor generated in said boiler, said evaporator comprising a plurality of individual sections, a storage chamber connected to each of said sections, a twin gas lift pump connected to receive liquid refrigerant from said liquefying means and to discharge separate and equal streams thereof into each of said storage chambers, means for directing a portion of said pressure equalizing medium into said twin gas lift pump to operate the same, and thermostatic means sealed entirely within said system constructed and arranged to allow discharge of liquid refrigerant only from a selected one of said storage chambers and circulation of pressure equalizing medium through only that section of the evaporator which is receiving liquid refrigerant from said selected storage chamber.

9. Refrigerating apparatus comprising a pair of ice-freezing evaporator sections, a fast-freezing evaporator connected to each of said icefreezing sections, liquid refrigerant supply means,

a pair of refrigerant storage chambers, means connecting each of said storage chambers to an associated ice-freezing evaporator section, a twin gas lift pump connected to transfer refrigerant from said supply means to said storage chambers, means for controlling said means connecting said storage chambers to said ice-freezing evaporator sections, and a thermostat in each of said icefreezing evaporator sections for actuating said.

last-mentioned means.

10. Refrigerating apparatus comprising a pair of ice-freezing evaporator sections, a fast-freezing evaporator connected to each of said icefreezing sections, liquid refrigerant supply means,

a pair of refrigerant storage chambers, means connecting each of said storage chambers to an associated ice-freezing evaporator section, a twin gas lift pump connected to transfer refrigerant from said supply means to said storage chambers, means for-controlling said means connecttrol chamber, means dividing said control chaming said storage chambers to said ice-freezing evaporator sections, a thermostat in each of said ice-freezing evaporator sections for actuating said last-mentioned means, means for supplying a pressure equalizing medium to said evaporator sections, and means actuated by said thermostatic means for governing the flow of pressure equalizing medium through said evaporator sections.

11. Refrigerating apparatus comprising a conber into a pair of storage compartments, an inert gas inlet compartment and an inert gas outlet compartment, a pair of evaporating elements communicating with said inlet and outlet compartment, control valve means' communicating each of said storage chambers with one of said, evaporators, valve means constructed and arranged to prevent communication between said inlet compartment and a selected one of said evaporators, snap-acting means for actuating all of said valve means, thermostatic means for actuating said snap-acting means, means for sup-' plying refrigerant to said storage compartments, and means for supplying a pressure equalizin medium to said inlet compartment.

12. Refrigerating apparatus comprising a pair of evaporating elements, a water tank mounted in heat transfer relationship with said evaporating elements at a plurality of points, a source of refrigerant including a liquefying element, means for supplying a pressure equalizing medium to said evaporating elements, a twin gas lift pump for conveying refrigerant from said liquefying element to said evaporating elements and control means constructed and arranged alternately to prevent supply of liquid refrigerant and pressure equalizing medium to one of said evaporating elements until ice blocks of a predetermined size have been formed in those portions of said water tank in heat exchange relationship with the other of said evaporating elements and then to render said other evaporating element inoperative and to permit supply of liquid refrigerant and pressure equalizing medium to said one evaporating element.

13. Refrigerating apparatus comprising a plurality of evaporating elements, liquid refrigerant supply means, refrigeration demand responsive means for directing a portion of such liquid supply along with previously collected liquid refrigerant into a selected one of said evaporating elements, means for collecting-the portion of such liquid supply which is not so directed, and means for supplying a pressure equalizing medium to said evaporating elements.

14. Refrigerating apparatus comprising a plurality of evaporating elements, liquid refrigerant supply means, refrigeration demand responsive means for directing a portion of such liquid supply along with previously collected liquid refri I 

